[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181734
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON 18 APR 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM
THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON
SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 13N0 10N10W 1N29W 3N40W EQ50W.
SCATTERED MODERATE/STRONG CONVECTION IS DEVELOPING S OF THE AXIS
OVER BURKINA FASO AND THE IVORY COAST FROM 6N-13N BETWEEN 1W-6W.
SCATTERED MODERATE S OF THE AXIS WITHIN 45 NM OF A LINE FROM
2N14W TO 2N20W. NUMEROUS MODERATE WITHIN 75 NM OF THE AXIS
BETWEEN 22W-29W. SCATTERED MODERATE FROM EQ-5N BETWEEN 33W-42W.

...DISCUSSION...

GULF OF MEXICO...
A 1027 MB HIGH IS CENTERED NEAR THE GEORGIA/FLORIDA BORDER AND
COVERS THE ENTIRE GULF OF MEXICO REGION AS WELL AS THE ERN THIRD
OF MEXICO. THE RIDGE IS PRODUCING MAINLY LIGHT/MODERATE E/SE
WINDS OVER THE AREA...AND IS ALSO INCREASING MOISTURE VALUES
ACROSS EXTREME NE MEXICO AND MUCH OF TX. A CUT-OFF MID/UPPER LOW
SPINNING FROM NRN KANSAS INTO NEBRASKA IS DRAGGING A TROF SW
INTO W TEXAS AND NRN MEXICO WHICH IS TAPPING INTO THIS MOISTURE
AND PRODUCING WIDELY SCATTERED SHOWERS/TSTMS PRIMARILY N OF 27N
INTO SRN TX. A 100 KT SUBTROPICAL JET IS APPROACHING THE W COAST
OF MEXICO AND IS ALLOWING A FEW HIGH CLOUDS TO SPILL OVER INTO
THE WRN GULF OF MEXICO BUT OTHERWISE SKIES ARE PARTLY
CLOUDY...BECOMING CLEARER FARTHER E TOWARDS FLORIDA.
SHOWERS/TSTMS WILL CONTINUE TO DEVELOP OVER S/SE TX THRU THE DAY
AS THE SHORTWAVE SWINGS TO THE E...AND THEN SHOWERS/TSTMS WILL
BE POSSIBLE OVER THE E GULF AND FLORIDA WED AND THU AS THE
SYSTEM SKIRTS OFF THE E COAST.

CARIBBEAN...
AN OLD DISSIPATING FRONTAL TROF HAS MOVED VERY LITTLE OVER THE
PAST SEVERAL DAYS AND REMAINS ALONG A LINE FROM HISPANIOLA SW
JUST OFF THE COAST OF JAMAICA NEAR 17N77W THEN TO THE COAST OF
NICARAGUA. QSCAT IMAGERY INDICATES THAT THE BOUNDARY HAS EVOLVED
INTO A CLASSIC SHEAR AXIS WITH WINDS 20-25 KT TO THE N OVER THE
NW CARIBBEAN AND 10-20 KT TO THE S. THIS IS PRODUCING ENOUGH
LOW-LEVEL CONVERGENCE FOR WIDELY SCATTERED SHOWERS/ISOLATED
TSTMS TO DEVELOP UP TO 150 NM N OF THE AXIS...SOME OF WHICH HAVE
BEEN OCCASIONALLY AFFECTING PARTS OF HISPANIOLA...JAMAICA...AND
COASTAL NICARAGUA. THE UPPER LEVELS ARE DOMINATED BY MOSTLY SWLY
FLOW SE OF A LINE FROM THE WINDWARD PASSAGE TO NICARAGUA NOW
THAT THE UPPER HIGH HAS SLID ALL THE WAY TO THE COAST OF
GUYANA...AND THIS HAS OPENED THE GATES FOR DEEP TROPICAL
MOISTURE TO BE ADVECTED WELL INTO THE CNTRL ATLC AHEAD OF THE
FRONT IN THAT AREA. SHOWERS WILL CONTINUE TO AFFECT THE W
CARIBBEAN AT LEAST FOR THE NEXT 72 HRS AS THE SFC BOUNDARY
SLOWLY DISSIPATES...BUT AREAS FARTHER NE FROM HISPANIOLA TO
PUERTO RICO COULD STILL SEE VERY SHOWERY WEATHER INTO THE
WEEKEND.

ATLANTIC...
SFC HIGH PRES IS BUILDING FROM WEST TO EAST OFF THE U.S. COAST
AND IS FINALLY PUSHING THE STORM LOW THAT AFFECTED THE CAROLINA
COAST OVER THE WEEKEND OUT TO SEA. A BROAD UPPER LEVEL LONGWAVE
TROF HAS BEEN SLOW-MOVING OVER THE W ATLC WATERS...STRETCHING
ALONG A LINE FROM 32N63W TO THE S/CNTRL BAHAMAS...BUT A
SHORTWAVE DISTURBANCE NEAR BERMUDA IS TRANSFERRING SOME MOMENTUM
TO THIS FEATURE AND FINALLY PUSHING IT TO THE E. A LINEAR COLD
FRONT EXTENDS INTO THE AREA ALONG 32N53W 23N64W...THEN AS A
STATIONARY FRONT TO THE N COAST OF THE DOMINICAN REPUBLIC...WITH
SCATTERED MODERATE CONVECTION WITHIN 75 NM OF THE BOUNDARY N OF
24N AND SCATTERED SHOWERS/TSTMS UP TO 120 NM N OF THE BOUNDARY S
OF 24N. A STRONG 1027 MB SUBTROPICAL HIGH DOMINATES THE
REMAINDER OF THE ATLC...CENTERED NEAR 31N32W AND RIDGE EXTENDING
SW TO 20N62W...BUT THE WEATHER IN SOME PARTS OF THE E ATLC IS
BEING AFFECTED BY THE FEATURES IN THE MID/UPPER LEVELS. A
STATIONARY CUT-OFF MID/UPPER LOW IS LOCATED ABOUT 550 NM NW OF
THE CAPE VERDE ISLANDS NEAR 22N33W WITH A TROF EXTENDING SW TO
5N40W AND IS DRAWING A GOOD AMOUNT OF HIGH CIRRUS NWD OFF THE
COAST OF AFRICA BETWEEN 16W-30W. THE LOW WILL REMAIN ITS OWN
ENTITY THRU FRI AS IT DRIFTS EWD TO THE COAST OF AFRICA...AND
THIS SHOULD THEN BEGIN TO BRING SOME OF THE HIGH CIRRUS INLAND
OVER SENEGAL...MAURITANIA...AND WESTERN SAHARA.

$$
BERG


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